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1Author    I. F. Kaetsu, T. Yoshii, FujimuraRequires cookie*
 Title    Effect of Viscous Solvents and Monomer on Conservation of Intact and Immobilized Chloroplasts  
 Abstract    0 2 evolution activity of PS II in chloroplast stored in buffer including various supercooling solvents was studied. Viscous solvents such as polyethylene glycol (PEG) was remarkably effective for the increase o f lifetime o f intact chloroplast. Lifetime of immobilized chloroplast by means of radiation polymerization was prolonged more than 40 days in buffer including PEG 70% (v/v). It was found that viscous solvents having PEG units in molecular chain were effective and methoxypolyethyleneglycol methacrylate monomer (M-23G) was most suitable as a im­ mobilization carrier. The immobilized chloroplast with M-23G retained the high activity yield more than 30 days in buffer including PEG. 
  Reference    Z. Naturforsch. 35c, 1052—1056 (1980); received September 2 1980 
  Published    1980 
  Keywords    Chloroplast, Immobilization, Oxygen Evolution, Viscous Solvent, Radiation Polymerization 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-1052.pdf 
 Identifier    ZNC-1980-35c-1052 
 Volume    35 
2Author    S. Achio, M. Iyairi, N. Th, H. SchatzRequires cookie*
 Title    Oxygen-Evolving Extracts from a Thermophilic Cyanobacterium Synechococcus sp  
 Abstract    Spheroplast membranes o f a thermophilic cyanobacterium Synechococcus sp. have been treated with the detergent lauryldim ethylam ine oxide (LD A O). The resulting extracts show (1) light-induced 0 2 evolution with artificial electron acceptors, (2) four-fold enhancement o f the 0 2 evolution relative to chlorophyll, (3) parallel increase o f both the molar ratios o f PS 2/C hl and cyt b559/C hl in the extract, (4) dissociation o f the auxiliary pigm ent phycocyanin upon treatment with LDAO, but still tight association o f allophycocyanin to the photosystem 2 preparation. 
  Reference    Z. Naturforsch. 38c, 44 (1983); received July 2/Septem ber 13 1982 
  Published    1983 
  Keywords    Cyanobacteria, Oxygen Evolution, Photosystem 2, Allophycocyanin, Energy Transfer 
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 TEI-XML for    default:Reihe_C/38/ZNC-1983-38c-0044.pdf 
 Identifier    ZNC-1983-38c-0044 
 Volume    38 
3Author    HainfriedE A Schenk, M. Argarete, Neu-M ÜllerRequires cookie*
 Title    Der Einfluß von Cycloheximid und Chloramphenicol auf die Biosynthese der Photosynthese-Pigmente in Cyanophora paradoxa Korsch I. Photosynthetische Sauerstoffproduktion Photosynthetic O xygen Evolution  
 Abstract    The Influence o f C yclohexim ide and C hloram phenicol on the B iosynthesis o f the Photosynthetic P igm ents in Cyanophora paradoxa I. It is not clear whether an endocytobiont is able to develop during a long evolution tim e only to an organelle like cell structure (defect m utant) with a high degree of m etabolic dependency or also to a perfect cell organelle with genetical dependency to the host nucleus (intercom partm ental translocation of proteins an d /o r gene transfer) in the sense of the Serial Endocytobiosis Hypothesis (SEH). Cyanocyta korschokoffiana, the endocyanelle of C. paradoxa, seems to be a very suitable object to answer this question. Therefore we have studied the influence o f the translation inhibitors cycloheximide (CHI) and chloramphenicol (CA) on the biosynthetic behaviour of this cyanobacterial endocytobiont regarding the photosynthetic oxygen during 20 h developing and incubation time. After dilution with fresh culture m edium the oxygen evolution of the control culture remains nearly constant, if it is related to the phycocyanin content, whereas it increases slowly to a constant level relating to the chlorophyll content (nearly 140-150% o f the starting activity). CHI and CA show a rapid effect on the oxygen evolution. At the first 8 -10 h the oxygen evolution of cultures treated with CA are hardly dim inished and rem ain m ore or less constant with regard to the starting activity, but that of cultures treated with CHI decreases strongly. After 24 h the CHI treated flagellate is photosynthetically inactive and far-reaching destroyed (microscopic observations), indicating that CHI has beside the inhibition effects on protein synthesis also secondary effects on the stability o f m em branes o f C. paradoxa. Der apochlorotische Flagellat Cyanophora 
  Reference    Z. Naturforsch. 38c, 978—983 (1983); received July 19 1983 
  Published    1983 
  Keywords    Cyanophora paradoxa, Photosynthetic Activity, Oxygen Evolution, Chlorophyll, Phycocyanin 
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 TEI-XML for    default:Reihe_C/38/ZNC-1983-38c-0978.pdf 
 Identifier    ZNC-1983-38c-0978 
 Volume    38 
4Author    J. Messinger, S. Pauly, H. T. WittRequires cookie*
 Title    The Flash Pattern of Photosynthetic Oxygen Evolution after Treatment with Low Concentrations of Hydroxylamine as a Function of the Previous Sj/So-Ratio Further Evidence that N H 2O H Reduces the Water Oxidizing Complex in the Dark  
 Abstract    Flash induced oxygen evolution patterns o f isolated PS II complexes from the cyanobacteri­ um Synechococcus were measured with a Joliot-type electrode. By suitable preflash and dark adaptation procedures, samples were prepared in the state Si (100%), as well as enriched in S0 (60% S0, 40% S,). After treatment with low concentrations o f N H 2O H (< 100 jjm), the two flash patterns were identical. This is further evidence for a reduction o f the water oxidizing complex by hydroxylamine in the dark. Two reduced states (S_, and S_2) below S0 are formed by this reduction. 
  Reference    Z. Naturforsch. 46c, 1033—1038 (1991); received June 6 1991 
  Published    1991 
  Keywords    Photosynthesis, Oxygen Evolution, Hydroxylamine, S-States ( Synechococcus) 
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 TEI-XML for    default:Reihe_C/46/ZNC-1991-46c-1033.pdf 
 Identifier    ZNC-1991-46c-1033 
 Volume    46 
5Author    NavassardV. Karapetyanab, Ute Windhövel3 ', AlfredR. Holzwarthc, Peter BögeraRequires cookie*
 Title    Physiological Significance of Overproduced Carotenoids in Transformants of the Cyanobacterium Synechococcus PCC7942  
 Abstract    The functional location of carotenoids in the photosynthetic apparatus of -crtB and -pys transformants of the cyanobacterium Synechococcus PCC7942 was studied and compared with a control strain -pF P l-3. These transformants overproduce carotenoids due to the insertion of an additional foreign phytoene synthase gene. A higher carotenoid content was found for -crtB and -pys transformants both in whole cells and isolated membranes; the -crtB transformant was also enriched with chlorophyll. 77-K fluorescence emission and excita­ tion spectra of the phycobilin-free membranes were examined for a possible location of overproduced carotenoids in pigment-protein complexes in situ. A similar ratio of the ampli­ tudes of fluorescence bands at 716 and 695 nm emitted by photosystems I and II, found for the three strains, indicates that the stoichiometry between photosystems of the transformants was not changed. Overproduced carotenoids are not located in the core antenna of photosys­ tem I, since 77-K fluorescence excitation spectra for photosystem I of isolated membranes from the studied strains do not differ in the region of carotenoid absorption. When illumi­ nated with light of the same intensity but different quality, absorbed preferentially by either carotenoids, chlorophylls or phycobilins, respectively, oxygen evolution was found always higher in the transformants -crtB and -pys than in -p F P l-3 control cells. Identical kinetics of fluorescence induction of all strains under carotenoid excitation did not reveal a higher activity of photosystem II in cells enriched with carotenoids. It is suggested that overpro­ duced carotenoids of the transformants are not involved in photosynthetic light-harvesting; rather they may serve to protect the cells and its membranes against photodestruction. 
  Reference    Z. Naturforsch. 54c, 191—198 (1999); received December 18 1998 
  Published    1999 
  Keywords    Carotenoid, Chlorophyll, Cyanobacterium, Fluorescence, Oxygen Evolution 
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 TEI-XML for    default:Reihe_C/54/ZNC-1999-54c-0191.pdf 
 Identifier    ZNC-1999-54c-0191 
 Volume    54 
6Author    M. D. Arie-Jose, ElrieuRequires cookie*
 Title    The Effects of 3-(3,4-Dichlorophenyl)-l,l-dimethylurea on the Photosynthetic Oxygen Complex  
 Abstract    In the presence o f trypsin and ferricyanide as external electron acceptor, lettuce chloroplasts are resistant to DCM U, showing that the inhibitory site o f D C M U is only situated on the accep­ tor side o f photosystem II. However, kinetic properties o f the oxygen evolving com plex are m od i­ fied at non-saturating concentrations o f D C M U . These changes are interpreted in terms o f a model with two distinct charges separation systems on the sam e center: the auxiliary donor-acceptor system D Q L implicated in the transitions S| -» • S 2 and S2 -*■ S 3 would be m uch less affected by DCM U than the main donor-acceptor system Y Q H after the first flash. 
  Reference    Z. Naturforsch. 39c, 347—350 (1984); received N ovem ber 28 1983 
  Published    1984 
  Keywords    Herbicides, Oxygen Evolution, Photosystem II, Electron Acceptors, Electron D onors 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0347.pdf 
 Identifier    ZNC-1984-39c-0347 
 Volume    39 
7Author    G. Renger, R. H. Agem Ann, W.F J V Erm AasRequires cookie*
 Title    Studies on the Functional Mechanism of System II Herbicides in Isolated Chloroplasts  
 Abstract    The effect o f specific proteolytic enzymes on variable fluorescence, p-benzoquinone-m ediated oxygen evolution, PS II herbicide (atrazine and brom oxynil) binding, and protein degradation has been analyzed in isolated class II pea chloroplasts. It was found that: 1. Trypsin and a lysine-specific protease effectively reduce the m axim um chlorophyll-a flu o­ rescence yield, whereas the initial fluorescence remains alm ost constant. At the sam e number o f enzymatic activity units both proteases have practically the sam e effect. 2 Trypsin and a lysine-specific protease inhibit the /»-benzoquinone-m ediated flash-induced oxygen evolution with trypsin being markedly more effective at the sam e num ber o f activity units o f both enzymes. Unstacked thylakoids exhibit a higher sensitivity to proteolytic degrada­ tion by both enzymes. 3. Trypsin and a lysine-specific protease reduce the binding capacity o f [14C]atrazine, but enhance that o f [l4C]bromoxynil (at long incubation tim es trypsin treatm ent also impairs bromoxynil binding). At the same specific activity a m arkedly longer treatm ent is required for the lysine-specific protease in order to achieve the same degree o f m odification as w ith trypsin. 4. Trypsin was found to attack the rapidly-turned-over 32 kD a-protein severely, whereas the lysine-specific protease does not m odify this polypeptide. On the other hand, the lysine-specific protease attacks the light harvesting com plex II. 5. Under our experimental conditions an arginine-specific protease did not affect chlorophyll-a fluorescence yield, /?-benzoquinone-mediated oxygen evolution, herbicide binding and the p oly­ peptide pattern. Based on these results a m echanism is proposed in w hich an as yet unidentified polypeptide with exposable lysine residues, as well as the lysine-free "Q B-protein" regulate the electron transfer from Q ^ to Q B and are involved in herbicide binding. 
  Reference    Z. Naturforsch. 39c, 362—367 (1984); received Decem ber 1 1983 
  Published    1984 
  Keywords    Chloroplasts, Proteolytic Enzymes, Fluorescence, Oxygen Evolution, H erbicide Binding 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0362.pdf 
 Identifier    ZNC-1984-39c-0362 
 Volume    39 
8Author    É. Va, H. Ideg, SándorD. Em EterRequires cookie*
 Title    Binary Oscillation of Delayed Luminescence: Evidence of the Participation of Qb in the Charge Recombination  
 Abstract    The flash-induced oscillation of a slowly decaying component of delayed luminescence (half time ~ 42 s) was investigated in spinach chloroplasts for various redox states of the secondary acceptor pool (Q B)-In preilluminated chloroplasts (30 s light followed by 5 min dark) the slow component exhibited a period-4 oscillation as a function of flash number. Upon oxidation of a major part of the QB pool by dark-adaptation or by ferricyanide treatment of chloroplasts, the period-4 oscillation was converted into a period-2 oscillation, providing direct experimental evi­ dence of the participation of QB in the charge recombination reaction. The measured oscillatory patterns could be simulated in model calculations by assuming that the slow component originates from charge recombination of the redox couples S2Q| 
  Reference    Z. Naturforsch. 40c, 827—831 (1985); received May 23/July 24 1985 
  Published    1985 
  Keywords    Delayed Luminescence, Oscillation, Oxygen Evolution, Secondary Quinone Acceptor, Chloroplast 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0827.pdf 
 Identifier    ZNC-1985-40c-0827 
 Volume    40 
9Author    V. A. Boichenko, V. V. Klimovb, S. R. Mayes3, J. Barber1, T. Echnology, M. Edicine, London Sw, A. Y., U. K.Requires cookie*
 Title    Characterization of the Light-Induced Oxygen Gas Exchange from the IC 2 Deletion Mutant of Synechocystis PCC 6803 Lacking the Photosystem II 33 kDa Extrinsic Protein  
 Abstract    The absence o f the extrinsic M n-stabilizing 33 kD a protein in the IC 2 mutant o f Synecho­ cystis PCC 6803 disturbs the redox cycling o f the water splitting system and retards the formation o f its higher S-states (I. Vass, K.. We have performed analyses o f the flash-induced oxygen exchange in the mutated cyanobacterium to clarify further the role o f the 33 kD a protein. Under aerobic conditions, both the wild type and IC2 mutant show a relative­ ly slow signal o f oxygen rise on the first flash which is increased about twice by the addition o f 10 (aM D C M U and significantly diminished by lowering the oxygen concentration in the medi­ um. According to action spectra measurements, this m ode o f apparent oxygen release is me­ diated by PS I and can be attributed to a light induced inhibition o f respiratory activity. In contrast to the wild type, having the usual oxygen evolution flash pattern with a periodicity o f four, the IC2 mutant shows a binary oscillation pattern o f flash-induced respiratory oxygen exchange at a flash frequency 10 Hz, being dampened with D C M U or by a lower flash fre­ quency (< 1 Hz). Oxygen evolution due to water splitting is clearly seen in the IC2 mutant when background far-red illumination is applied to saturate the signal due to respiratory inhi­ bition, but a quadruple oscillatory com ponent o f flash-induced oxygen evolution appears only in the presence o f artificial electron acceptors under partial aerobic conditions. The mutant possesses a higher PS I/PS II ratio compared to the wild type, as judged from both the flash-induced yields and quantum efficiencies o f the steady-state rates o f the oxygen exchange reac­ tions. Estimates o f antenna sizes indicate about a 20% decrease o f optical cross-section at 675 nm o f the PS II unit in IC 2 mutants in comparison with the wild type. It is suggested that the absence o f the 33 kDa protein leads to a m odification o f the PS II assembly and because o f the slowing down o f the S-state cycle, the rate o f cyclic electron flow around PS II is enhanced. It seems that the absence o f the 33 kD a protein in Synechocystis 6803 also disturbs energy transfer between adjacent PS II core complexes and may also alter their association with the phycobilisomes. 
  Reference    Z. Naturforsch. 48c, 224—201 (1993); received December 10 1992 
  Published    1993 
  Keywords    Photosystem II, Oxygen Evolution, 33 kD a Protein, Synechocystis, Mutants 
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 TEI-XML for    default:Reihe_C/48/ZNC-1993-48c-0224.pdf 
 Identifier    ZNC-1993-48c-0224 
 Volume    48 
10Author    G. Renger, H. M. Gleiter, E. Haag, F. ReifarthRequires cookie*
 Title    Photosystem II: Thermodynamics and Kinetics of Electron Transport from Qa" to Q b(Q b' ) and Deleterious Effects of Copper(II)  
 Abstract    Studies on thermodynamics and kinetics o f electron transfer from QA~ to QB(QB") were per­ formed by m onitoring laser flash induced changes o f the relative fluorescence emission as a function o f temperature (220 K < T < 310 K) in isolated thylakoids and PS II membrane frag­ ments. In addition, effects o f bivalent metal ions on PS II were investigated by measuring conven­ tional fluorescence induction curves, oxygen evolution, manganese content and atrazine bind­ ing mostly in PS II membrane fragments. It was found: a) the normalized level o f the fluores­ cence remaining 10 s after the actinic flash (FJF0) steeply increases at temperatures below -1 0 to -2 0 °C, b) the fast phase o f the transient fluorescence change becomes markedly retard­ ed with decreasing temperatures, c) am ong different cations (Cu2+, Zn2+, Cd2+, N i2+, Co2+) only Cu2+ exhibits marked effects in the concentration range below 100 jim and d) Cu2+ decreases the normalized variable fluorescence, inhibits oxygen evolution and diminishes the affinity to atrazine binding without affecting the number o f binding sites. The content o f about four manganeses per functionally competent oxygen evolving complex is not changed by [Cu2+] < 70 |iM. Based on these findings it is concluded: i) a temperature dependent equilibrium between an inactive (I) and active (A) state o f QA~ reoxidation by Q b(Qb) is characterized by standard 
  Reference    Z. Naturforsch. 48c, 234 (1993); received November 23 1992 
  Published    1993 
  Keywords    Photosystem II, Q B-Site, Copper(II) Effects, Fluorescence, Oxygen Evolution 
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 TEI-XML for    default:Reihe_C/48/ZNC-1993-48c-0234.pdf 
 Identifier    ZNC-1993-48c-0234 
 Volume    48 
11Author    KlausP B Ad Er, Judith SchülerRequires cookie*
 Title    Inhibition of the Photosynthetic Electron Transport by Pyrethroid Insecticides in Cell Cultures and Thylakoid Suspensions from Higher Plants  
 Abstract    Synthetic pyrethroid insecticides with different molecular structures have been investigated with respect to their effect on photosynthetic electron transport reactions in chloroplast sus­ pensions and cell cultures from higher plants. The fluorescence induction curves of tobacco (Nicotiana tabacum) leaves and tomato cells were substantially affected by permethrin and cypermethrin resulting in a strong increase of the maximum fluorescence. Application of different concentrations (0.3-1.2 m M) of the respective chemical abolishes virtually any ki­ netics of the normal Kautsky effect. Oxygen evolution from cell cultures from tomato (Ly-copersicon peruvianum) was completely inhibited by cypermethrin. Analysis of partial reac­ tions of the photosynthetic electron transport showed that both a methylviologen-mediated Mehler reaction and a ferricyanide-driven Hill reaction were quantitatively inhibited by e.g. fenvalerate. On the other hand, neither a silicomolybdate-driven Hill reaction nor a methylvi-ologen-driven Mehler reaction using dichlorophenol indophenol/ascorbate as electron donors could be inhibited by the pyrethroid. The analyses suggest that pyrethroid insecticides in­ terfere with the photosynthetic electron transport at the same site as urea-type herbicides do. Depending on the molecular structure and on the halogen compound in the molecule, however, different pyrethroids are more or less phytotoxic to the investigated photosynthetic membranes -cypermethrin with two Cl-substituents requires much higher concentrations to be applied for significant inhibition of the electron transport reactions than the Br-derivative deltamethrin does. Moreover, qualitative differences have to be taken into account. In the case of fenvalerate the effect seems to exist in a type of all-or-nothing reaction when the reaction centres are inhibited by the pyrethroid. None of the S-states nor the transition probabilities are specifically influenced by increasing concentrations of fenvalerate. In the case of deltamethrin, however, it was found that the overreduced state S_i is significantly increased at the expense of both Si and S(). Moreover, the miss parameter a is increased in the case of deltamethrin addition. The results and the significance of different substituents for the investigated pyrethroids are discussed. 
  Reference    Z. Naturforsch. 51c, 721—728 (1996); received April 25/June 20 1996 
  Published    1996 
  Keywords    Photosynthesis, Electron Transport, Oxygen Evolution, Pyrethroid Insecticide, Cell Culture 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0721.pdf 
 Identifier    ZNC-1996-51c-0721 
 Volume    51 
12Author    Günter Döhler, Jean-Claude Leclerc, M.Requires cookie*
 Title    Photosynthetic Adaptation in Synechococcus Cells  
 Abstract    The cyanobacterium Synechococcus (Anacystis nidulans, strain L 1401-1) grown under different light conditions showed variations in pigmentation. Ratios of photosynthetic pigments and the effect on quantum requirement and oxygen evolution were studied. An increase in the ratio of chlorophyll a forms with absorption maxima in the far red regime to total chlorophyll a forms was observed in cells grown in strong white light. The quantum efficiency of orange light (637 nm) -absorbed by phycocyanin — was higher after growth of Synechococcus in white than 
  Reference    Z. Naturforsch. 37c, 1075—1080 (1982); received August 12 1982 
  Published    1982 
  Keywords    Pigmentation, Quantum Requirement, Absorption Spectra, Oxygen Evolution, P 700, Synecho­ coccus 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-1075.pdf 
 Identifier    ZNC-1982-37c-1075 
 Volume    37 
13Author    Marie-Jose DelrieuRequires cookie*
 Title    Evidence for Unequal M isses in Oxygen Flash Yield Sequence in Photosynthesis  
 Abstract    The numerical analysis of the oxygen flash yield Yn sequences, alone, does not allow to choose between two models: equal S state misses with non negligible double hits or unequal misses with nearly no double hits. Nevertheless, the com parison o f the sequences in different conditions shows that the equal miss model is unrealistic: in very different experimental conditions (non saturating flash, different batch o f Chlorella or chloroplasts), a parallel variation of the hom o­ geneous miss and double hit factors is observed. This correlation seems strange within the equal miss model: misses come from incomplete reaction (i.e. for exemple insufficient light) and double hits i.e. double advancem ent come, in principle, from excessive light or too long flash; for these reasons, opposite variation of misses and double hits as a function of light intensity are ex­ pected. W ithin the equal miss model the inverse is exactly observed: at low flash light intensity (11%) which increases the misses, 16% of double hits are needed, which is quite unrealistic. In contrast, the unequal miss model explains such result quite naturally by a m athem atical property: any theoretical sequence with only a unique S state miss and no double hit can be fitted with homogeneous misses and double hits, which increase in parallel as a function o f the damping. Evidence for unequal misses in oxygen flash yield sequence is provided by the heterogeneous properties of the light saturation curves (M. J. D elrieu, Biochim. Biophys. Acta 592, 4 7 8 -4 9 4 (1980)). At high flash intensity, all, excepted the transition S ' 2 -*■ S3 , are saturated; the transition £ 2 -* S3 is far from saturation and its very large saturating light intensity is actually not known. A comparative study, in the same chloroplast batch, o f the oxygen yield patterns with attenuated flashes and of the experimental saturation curves of S states shows that only photo­ chemical misses (due to non saturation) exist. At high intensity, there is only a unique miss for the transition S 2 S 3 i.e. the probability for this transition is low. A model involving a second acceptor could explain the slow increase of transition probability o f S ' 2 -* S3 at high flash intensity. 
  Reference    Z. Naturforsch. 38c, 247—258 (1983); received N ovem ber 16 1982 
  Published    1983 
  Keywords    Oxygen Evolution, Photosystem II, M atrix Analysis, N on Saturating Flash Sequence, Electron Acceptor 
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 TEI-XML for    default:Reihe_C/38/ZNC-1983-38c-0247.pdf 
 Identifier    ZNC-1983-38c-0247 
 Volume    38 
14Author    Anastasios Melis, C. Onrad, W. M. Ullineaux, JohnF. AllenRequires cookie*
 Title    Acclimation of the Photosynthetic Apparatus to Photosystem I or Photosystem II Light: Evidence from Quantum Yield Measurements and Fluorescence Spectroscopy of Cyanobacterial Cells  
 Abstract    Cells of the cyanobacterium Synechococcus 6301 were grown under illumination whose spectral composition favoured absorption either by the phycobilisome (PBS) light-harvesting antenna of photosystem II (PS II) or by the chlorophyll (Chi) a light-harvesting antenna of photosystem I (PS I). Cells grown under PS I-light developed relatively high PS II/PS I and PBS/Chl ratios. Cells grown under PS II-light developed relatively low PS II/PS I and PBS/Chl ratios. Thus, the primary difference between cells in the two acclimation states appeared to be the relative concentration of PBS-PS II and PS I complexes in the thylakoid membrane. Measurements of the quantum yield of oxygen evolution suggested a higher efficiency of cellular photosynthesis upon the adjustment of photosystem stoichiometry to a specific light condition. The quantum yield of oxygen evolution was nevertheless lower under PBS than Chi excitation, suggesting quenching of excitation energy in the photochemical apparatus of PS II in Synechococcus 6301. This phenomenon was more pronounced in the PS II-light than in the PS I-light grown cells. Room temperature and 77 K fluorescence emission spectroscopy indicated that excess excitation energy in the PBS was not transferred to PS I, suggesting the operation of a non-radiative and non-photochemical decay of excitation energy at the PBS-PS II complex. This non-photochemical quenching was specific to conditions where excitation of PS II occurred in excess of its capacity for useful photochemistry. 
  Reference    Z. Naturforsch. 44c, 109 (1989); received October 1 1988 
  Published    1989 
  Keywords    Photosystem Stoichiometry, Thylakoid Membrane, Light-Harvesting, Excitation Energy Dis­ tribution, Oxygen Evolution 
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 TEI-XML for    default:Reihe_C/44/ZNC-1989-44c-0109.pdf 
 Identifier    ZNC-1989-44c-0109 
 Volume    44 
15Author    W. I. Gruszecki3, K. Strzałkab, A. R. Adunzc, J. K. Rukb, G. H. SchmidcRequires cookie*
 Title    Blue Light-Enhanced Photosynthetic Oxygen Evolution from Liposome-Bound Photosystem II Particles; Possible Role of the Xanthophyll Cycle in the Regulation of Cyclic Electron Flow Around Photosystem II?  
 Abstract    Light-driven electron transport in liposom e-bound photosystem II (PS-II) particles be­ tween water and ferricyanide was monitored by bare platinum electrode oxymetry. The m odi­ fication of the experimental system with the exogenous quinones a-tocopherol quinone (a-TQ) or plastoquinone (PQ) resulted in a pronounced effect on photosynthetic oxygen evolution. The presence o f a-tocopherolquinone (a-T Q) in PS-II samples decreased the rate of red light-induced oxygen evolution but increased the rate o f green light-induced oxygen evolution. Blue light applied to the assay system in which oxygen evolution was saturated by red light resulted in a further increase o f the oxygen signal. These findings are interpreted in terms of a cyclic electron transport around PS-II, regulated by an excitation state of ß-carotene in the reaction centre of PS-II. A mechanism is postulated according to which energetic coupling of ß-carotene in the reaction centre of PS-II and that o f other antenna carotenoid pigments is regulated by the portion of the xanthophyll violaxanthin, which is under control of the xanthophyll cycle. 
  Reference    Z. Naturforsch. 50c, 61—6 (1995); received June 15/November 11 1994 
  Published    1995 
  Keywords    a-Tocopherol Quinone, Plastoquinone-9, Oxygen Evolution, Photosystem II, Cyclic Electron Transport, Xanthophyll Cycle 
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 TEI-XML for    default:Reihe_C/50/ZNC-1995-50c-0061.pdf 
 Identifier    ZNC-1995-50c-0061 
 Volume    50 
16Author    W.I G Ruszeckia, K. Strzałk, K.P B Ad Erc, A. R. Adunzc, G. H. SchmRequires cookie*
 Title    Involvement of the Xanthophyll Cycle in Regulation of Cyclic Electron Flow around Photosystem II  
 Abstract    In our previous study (Gruszecki et al., 1995) we have postulated that the mechanism of cyclic electron transport around photosystem II, active under overexcitation of the photosyn­ thetic apparatus by light is under control of the xanthophyll cycle. The combination of dif­ ferent light quality and thylakoids having various levels o f xanthophyll cycle pigments were applied to support this hypothesis. In the present work photosynthetic oxygen evolution from isolated tobacco chloroplasts was measured by means o f mass spectrometry under conditions of high or low levels of violaxanthin, being transformed to zeaxanthin during dark incubation in an ascorbate containing buffer at pH 5.7. Analysis of oxygen evolution and o f light-induced oxygen uptake indicate that the de-epoxidation o f violaxanthin to zeaxanthin results in an increased cyclic electron transport around PS II, thus dimishing the vectorial electron flow from water. An effect similar to de-epoxidation was observed after incubation of thylakoid membranes with specific antibodies against violaxanthin. 
  Reference    Z. Naturforsch. 51c, 47 (1996); received September 22/O ctober 18 1995 
  Published    1996 
  Keywords    Xanthophyll Cycle, Cyclic Electron Flow, Photosystem II, Oxygen Evolution, Blue Light Effect, Mass Spectrometry 
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 TEI-XML for    default:Reihe_C/51/ZNC-1996-51c-0047.pdf 
 Identifier    ZNC-1996-51c-0047 
 Volume    51 
17Author    Yoshihiro Shiraiwa, GeorgH. SchmidRequires cookie*
 Title    Effect of the C 0 2-Concentration during Growth on the Oxygen Evolution Pattern under Flash Light in Chlorella  
 Abstract    Photosynthetic 0 2-evolution patterns were determined in cells of Chlorella vulgaris 211 — 11 h, grown under air enriched with 2% C 0 2 (High C 0 2-cells) and under ordinary air (Low C 0 2-cells). Oxygen evolution in these algae was measured as consequence of short saturating light flashes with the three electrode system according to Schmid and Thibault, Z. Naturforsch. 34c, 414 
  Reference    Z. Naturforsch. 41c, 269 (1986); received November 25 1985 
  Published    1986 
  Keywords    Oxygen Evolution, Flash Sequence, S-States, Carbonic Anhydrase, C 0 2-Effect, Chlorella 
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 TEI-XML for    default:Reihe_C/41/ZNC-1986-41c-0269.pdf 
 Identifier    ZNC-1986-41c-0269 
 Volume    41 
18Author    J. K. Ru K, K. B., Rd Ab>, A. R. Adunzc, K. Strzałka3, G. H. SchmRequires cookie*
 Title    Antagonistic Effects of a-Tocopherol and a-Tocoquinone in the Regulation of Cyclic Electron Transport around Photosystem II  
  Reference    Z. Naturforsch. 52c, 766—774 (1997); received August 22/ 
  Published    1997 
  Keywords    a-Tocopherol, a-Tocoquinone, Plastoquinone-A, Photosystem II, Cyclic Electron Transport, Oxygen Evolution, Thylakoid Membrane 
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 TEI-XML for    default:Reihe_C/52/ZNC-1997-52c-0766.pdf 
 Identifier    ZNC-1997-52c-0766 
 Volume    52